The major goal of the proposed research is to study the effects of treatments thought to prolong, shorten, or reverse the aging process on behavior of the Fischer 344 rat. The lifespan altering treatments will consist of undernutrition, exercise, injury to the central nervous system, repletion of deficient neurotransmitters and sensory loss. Major emphasis will be placed on the effects of these treatments on the behavioral declines that normally emerge during aging. Deficits in the following behavioral systems will be assessed periodically both during and following lifespan altering treatment: reflexive, motor, sensory, reactivity, sensory processing, attention, arousal, learning and memory. The long range goal of this research is to understand the effects of lifespan altering treatments on the overall behavioral state of the animal. Some of the important questions are as follows: Do generalized life-extending procedures such as undernutrition and voluntary exercise delay the development of all age-dependent behavioral deficits or is there selective alleviation of specific deficits? Does aging or loss of one system accelerate aging in all systems? Related systems? Or have no effect on other systems? And does alleviation of one type of deficit, such as restoration of motor function, affect other age-dependent deficits.